I got this set at the ETF meet last weekend and was working on it here and there during sanity breaks during finals last week. At the meet I and another collector saw the old orange drops in it and assumed it had been restored which turned out not to be the case.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2271_zpscdc0e783.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2271_zpscdc0e783.jpg.html)
I powered it up and got good sound but no HV. Well still assuming good caps I replaced nearly all the hroizontal/HV section tubes which were mostly bad anyway. The focus rect. tube was missing which I later found was for a reason. This landed me no net improvement. I then pulled the chassis, tested and replaced several caps in the horizontal section. This got me 11-15KV of HV, and a shrunken raster with pull-in on the sides.

What caused that?, what else I had to fix?, and what is still not working?...All that in my next exciting post.
Gotta run.

I got this set at the ETF meet last weekend and was working on it here and there during sanity breaks during finals last week. At the meet I and another collector saw the old orange drops in it and assumed it had been restored which turned out not to be the case.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2271_zpscdc0e783.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2271_zpscdc0e783.jpg.html)
I powered it up and got good sound but no HV. Well still assuming good caps I replaced nearly all the hroizontal/HV section tubes which were mostly bad anyway. The focus rect. tube was missing which I later found was for a reason. This landed me no net improvement. I then pulled the chassis, tested and replaced several caps in the horizontal section. This got me 11-15KV of HV, and a shrunken raster with pull-in on the sides.

What caused that?, what else I had to fix?, and what is still not working?...All that in my next exciting post.
Gotta run.
Power supply, voltage doubler problem? :scratch2:

That's where I'd start looking too. Check the cans, I bet the doubler is bad. Probably a 160 or so at 400 or so volts, been a long time since I've worked on any of my Zenith sets.

Replace the doubler. Also, check all resistors in the HV regulator section. An open one can also cause low HV.

Definitely start with the power supply. i too have a 25MC33 Zenith roundie and the electrolytic caps in the power supply are old enough now to cause trouble. This set should easily be able to produce 25 KV of high voltage which is what it should be adjusted for. These sets are full of brown drops which I'm not sure if they should be considered for replacement. My set still has most of them and I suppose one day it will need a full recap. Mine is in regular service and the only issue I have is the vertical acts like it is going to fail sometimes. I have not figured out the cause yet. The picture quality on these sets is fantastic, though, well worth the effort of a good restoration. Follow all the setup procedures in the Sams after restoration and you will be amazed at the performance.

Just went throught that on my CTC10 160@450VDC went open. I'll put a buck on it.

Yup it was the doubler. One of the doubler cans was wide open I did not have a 160uF 250v on hand so I subbed a 250uf 250V in for the time being and it corrected the horizontal shrinkage.
I kind of suspected it since I had a NEW doubler cap in my Silvertone fail and the symptoms were the same. After replacing the doubler I brought it up on a variac with my typical over caution, and as I approached line voltage I started to hear BAD corona sounds from the HV cage. My over caution proved merited; there was perhaps the worst corona I've yet seen in any set coming off the HV line. It had to be over an inch long, that purple spark, and if I cranked the variac closer to line voltage it turned to an intermittent arc that caused the CRT neck to light in step.:yikes: My camera did not want to capture it, but if you can see the black spot in the red wire with a tiny purple dot in the middle where the red wire is in-front of the HV rect. plate cap that's is where the arcing was. http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2282_zpscb9dbdae.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2282_zpscb9dbdae.jpg.html)
Since the wire had arced through I decided it was best to just replace the wire and HV connector suction cup with one salvaged from an abandoned SS set I scrapped. I also cleaned the rectifier cup, and removed the odd blob of clear silicon that someone put on the interior of the cup for reasons beyond my comprehension.
The cup did get better with a bath in the sink, but there was waxy dirt on the interior that soap and water refused to touch. To deal with that I broke out the big guns and used 'goof off' to remove it. That stuff can dissolve PVA and make the surface of those clear plastic covers on turntables turn rough and hazy. Since the HV cup is not clear and almost never seen I decided who cares if it messes with the finish if it gets the dirt off. Some pictures of this below.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2285_zps0cc8bfc3.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2285_zps0cc8bfc3.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2286_zps74ce0ff8.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2286_zps74ce0ff8.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2291_zps6da54ffc.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2291_zps6da54ffc.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2298_zps92bc55dd.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2298_zps92bc55dd.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2292_zps55d474da.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2292_zps55d474da.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2293_zps9df7a7d0.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2293_zps9df7a7d0.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2295_zpse2277322.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2295_zpse2277322.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2299_zps8cae01dd.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2299_zps8cae01dd.jpg.html)

I noticed while doing this that the focus rectifier tube socket was connected to nothing and that a 60's HV diode was installed. Not exactly correct but it is period and does seem to work decently so I think I'll leave it be for now.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2287_zps48dbd5a5.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2287_zps48dbd5a5.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2289_zpsf42dfacb.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2289_zpsf42dfacb.jpg.html)

Now I had a few problems remaining the set had not been given a proper gray scale, purity, or convergence setup in way too long. Also the vertical don't want to fill the bottom of the screen, and for some reason it seems the chassis hole marked 'vert. centering' looks to never been populated with a control...Ugh! That and I wanted to set it up before turning the color on.
It just don't want to be pure though, and the static convergence magnets don't have as much range as I'd like to see....I think I'll try a couple of spare purity rings I have stashed away next time I try to redo the set up. the results are below.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/th_DSCN2302_zpscb89530f.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2302_zpscb89530f.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2304_zpse2a974c6.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2304_zpse2a974c6.jpg.html)
After giving up on that I tried the color, but that was barely functioning. Most of the color stage tubes were weak or shorted so I swapped them and got almost perfect color bars....Only which one is supposed to be the blue-green bar and which is the green bar?
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2300_zps89083870.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2300_zps89083870.jpg.html)
There are also dirty tube sockets in the IF that I need to deal with, and for some reason it seems to tune channel three better with the tuner set to two.

I got this far without a schematic or any service data beyond the tube layout inside the cabinet, and I'm proud of that. But there are only a few tricks I've got left before I need to grab a reference to see exactly where it is off speck.

looks like its coming along nicely, if memory serves the HV rectifier is a 3at2? Ive got a bunch, being an RCA guy ,that I will never use, you are welcome to them, Bruce

looks like its coming along nicely, if memory serves the HV rectifier is a 3at2? Ive got a bunch, being an RCA guy ,that I will never use, you are welcome to them, Bruce

If I ever need them I'll contact you. I have a fairly good stock of HV rectifier tubes already though. Whenever I go to a radio club meet and TV tubes appear in the donation auction they usually end up coming home with me.

I hear you, it didn't take me too long to have a stash like an old time electronics store, have fun

With the Service/Normal switch in the service position, you should be able to verify vertical centering. If it's off-center there should be some nylon/fishline "loops" that are hanging out of the yoke. Pulling on one will affect the horzontal, the other loop the vertical. Most likely linearity and height will be difficult to achieve. See if the cathode capacitor is still the original and check B+ and load resistors.

You should have that set playing in no time!

Ohh, so that is what those strings are! I thought they were junk (like the pieces of HV wire some tech left) and tried to yank them out....Good thing I failed to yank them off. I probably messed up the settings when I pulled on them. If they are all the way back is there a way to get them forward?

Service switch kills ALL light on the screen so I did the screen adjustments by pulling one of the vertical wires to the yoke. It was off center(too high) when I did that so I guess I shouldn't have yanked those strings.

I'll have to look up the datasheet for the vertical output tube or get the sam's to find the cathode pin. By "B+ and load resistors" do you mean in the PS or vertical circuit?

Quote: By "B+ and load resistors" do you mean in the PS or vertical circuit?

Just referring to the vertical circuit at the moment!

Thanks for posting such detail on that set. I also have a 25MC33 Horiz output tube was cracked. I figured it had no osc, and overheated and cracked. I got a new tube but then didn't have the time to do any more this winter. Actually I still didn't turn it on, I found the bad tube just eyeballing around in the set before thinking about turning it on... I'm kinda inspired now to get busy on it....

That was really a hack that worked on that set sometime in it's past.
I'm guessing that the HV rectifier filament winding arced through at one time, so some clod used the focus rectifier winding instead.
It took some ingenuity to do it in that manner, but still hack at the same time. Plus poor lead dress.
When I found the same problem, I would cut out the filament winding and use a solid state replacement for the HV rectifier tube.
I still prefer a focus rectifier tube instead of that lousy stick. :thmbsp:

I'll try to find time in the afternoon to look at the vertical circuit.

I tried the upper yoke string today and it seemed to affect the vertical centering, but the only effect it seemed to have was to allow me to either get it close to centered or WAY too high.
The way the static static magnets for all functions on the CRT behave makes me feel like someone screwed the magnets up on purpose.

Mr Squirrel, reminded me that my set had the wrong HOT as found. It had a 6LB6 where a 6BS6 IIRC was supposed to be used.

I have no clue what the exact original HV configuration was, but the wire on the HV filament is a different color than the stubs on the focus socket so I doubt the focus wire was reused on the HV tube.

If I get a schematic for it I might revert the focus circuit, but aside from my CTC-4 project set my other roundys are SS focus and do fine that way. I will at least try to tweak the focus circuit to give me more range as I have it set to min on the pot to get best focus, and would prefer to find a peak somewhere in the range.

I'll try to find time in the afternoon to look at the vertical circuit.

I tried the upper yoke string today and it seemed to affect the vertical centering, but the only effect it seemed to have was to allow me to either get it close to centered or WAY too high.
The way the static static magnets for all functions on the CRT behave makes me feel like someone screwed the magnets up on purpose.

Mr Squirrel, reminded me that my set had the wrong HOT as found. It had a 6LB6 where a 6BS6 IIRC was supposed to be used.

I have no clue what the exact original HV configuration was, but the wire on the HV filament is a different color than the stubs on the focus socket so I doubt the focus wire was reused on the HV tube.

If I get a schematic for it I might revert the focus circuit, but aside from my CTC-4 project set my other roundys are SS focus and do fine that way. I will at least try to tweak the focus circuit to give me more range as I have it set to min on the pot to get best focus, and would prefer to find a peak somewhere in the range.

My 25MC33 has the correct focus circuitry and even after replacing the focus rectifier tube and the resistor string it still requires the pot to be at one end of the range for correct focus. That might just be the way these sets are. I have seen many old sets that require the focus control to be at one end of the range or the other to focus correctly.

It's not the way they are supposed to be, check ALL resistors in the focus circuit. Make sure they are correct, I mean like, spot on. I'll bet you find a bad one...
Edit: Also the POT can go to crap, I've replaced all of the above and was able to get the focus nice and sharp with the control set somewhere in the middle. Drifty resistors in related circuits can cause it to be off too.

I figured out how to get the vertical centered. Apparently neither of the strings is solely for horizontal or vertical centering. They each affect both axises in the same way centering rings did on monochrome sets.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2308_zps44fde2d6.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2308_zps44fde2d6.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2312_zps02ec05bb.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2312_zps02ec05bb.jpg.html)

I have the height pot maxed out and the linearity as high as it needs to be to fill the mask yet be as linear as I can get it. Tomorrow I'll try to pull the chassis to check for off value vertical resistors.

As a bonus the issue with the blue-green bar being green has gone away on it's own, and I now have good color rendition.

Tom! I'd still be tempted to restore the focus circuit to the original scheme.
Those focus sticks are selenium, not silicon! They are subject to getting weak and causing focus problems.
Of course, Mark is right, regarding those high value resistors, drastically changing value.
One of the first things I check is the electrolytic in the cathode circuit, of the vertical output tube when dealing with vertical size issues. :yes:

With out a schematic I don't feel like changing the focus circuit. I'd be more likely to just change the flavor of incorrectness on my own without data on the original(plus I don't think I have enough HV wire). It focuses DAMN sharp at the bottom of the controls range right now...Probably better than most color sets I own.
Thanks for the tip on the vertical lytic. I may have tested that one already. I'll need to trace it down to see if I did.

That looks great ! I assume your not going to fix the cataracts right now..........

Actually Before I read your post I pulled and prepped the CRT for cataract removal.... If the forecast of sun tomorrow is accurate I should have the jug back in by Sunday.

I'll get to the chassis tonight if I can.

Well I did the cataract removal today(well it was today before it hit midnight).
The tube is a Silver-Glo rebuild(I assume). The PVA was really weird...The outside edge was calcified for lack of a better word, and the center stuck to the face of the tube like Zenith type PVA.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/DSCN2315_zps813435fd.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/CRT%20cateract%20removal%20pictoral%20journal/DSCN2315_zps813435fd.jpg.html)

The sun was a tad patchy, and between it 16 cloths pins as wedges around the perimeter and a hair drier it barely wanted to come unglued around the edge. I went a bit far with the wedges and the safety glass cracked. I ended up chipping off the safety glass which was not fun.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/DSCN2313_zps2a3464c3.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/CRT%20cateract%20removal%20pictoral%20journal/DSCN2313_zps2a3464c3.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/DSCN2314_zps0f9964e0.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/CRT%20cateract%20removal%20pictoral%20journal/DSCN2314_zps0f9964e0.jpg.html)
All in all aside from the loss of the safety glass it seems to have turned out well.
Tomorrow I'll finish remounting it and resume work on the electronics.

Is it safe to use that tube without the safety glass? I would expect now you have no implosion protection.

I seem to recall someone saying that 70's "loss leader" roundys did not usually have safety glass installed when they were built so I'd imagine if it was okay then it should be okay now. I've never had a roundy CRT implode (knock on wood) and I've got 4 sets and 6 total CRTs, all of which I've handled at some point. The one I cataracted above even got tapped with a hammer on the screen a few times and is fine so I'm not all that worried.

If it is really that dangerous(or if I can't achieve purity on this tube) I have a spare Zenith CRT that was already cataracted(by me) with the safety glass siliconed back on. There is a tiny part of me that wants to put the Zenith tube in anyway for better authenticity.

Hi Tom, Great job on that nice Zenith roundie from the ETF MEET! By the way, nice GE Porta Color on top in the first picture! :-) :-) I'll check this afternoon and see if I have the Sams for your Zenith. Dave.

Hi Tom......You now have a 21FBP22A with the light gray face plate like my 21CT55's. The "A" signifies a rare-earth phosphored screen which should produce outstanding reds for you. Question: Does your rebuild have a noticiable glass weld on its neck where the new base is attached? Do all rebuilds have this tell-tail, anyone?..........Tom

If you could find the schematic that would be a big help. Flying blind is a good confidence builder until one starts to hit the sort of odd little bugs I'm dealing with. I'm enjoying the portacolor. There are a few tiny bugs I need to address(I think a couple controls need cleaning), but otherwise it works a lot better than what I'd expect from what I've read about portacolors.

Tom: Thanks for the info. It did have a dark tinted safety glass, but it got destroyed in the cataract removal. I don't know if this tube has a neck weld as I have never removed the neck hardware. My standard operating procedure when decating a tube that has already had the neck hardware adjusted is to pull the tube with all neck hardware on and plop the whole thing in the bucket I use as a stand during decating(I did have to hang the convergence adjustment chassis outside the bucket on this one though). This method has resulted in not having to re-setup the tube in several sets or to only have to make minimal touch-ups.
I may be able to answer your question soon. If a couple of things I'm going to try fail to get this tube to have acceptable purity. I'm going to assume the Silver-Glo that is in there now is defective and swap in my spare Zenith 21FBP22 CRT. I've degaussed the living bleep out of it, so about all I can think of doing now is to swap the purity rings and possibly the CRT.

Hi Tom, I DO have the Schematic!! Turns out it's the same as my 1965, 25MC43 chassis, according to the index. Send me a PM with your Email, when you have the chance to do so. Glad you're enjoying the Porta Color, it does have a decent picture, even as is, one reason I didn't put a high priority on working on it, too many "irons in the fire!" Dave

Great Dave! PM sent.

I was able to achieve decent purity(on any other set the more OCD parts of my mind would compel me to make it just a bit better) by flipping the rings 180 degrees and degaussing it even more rigorously than before. It was the first time I've been nuts enough to stuff my degauss coil inside a set let alone while the set was running.
The vertical out cathode cap tests like new on my Heathkit C-3 so I'm starting to test resistors.

[QUOTE=Electronic M;3071062]I seem to recall someone saying that 70's "loss leader" roundys did not usually have safety glass installed when they were built so I'd imagine if it was okay then it should be okay now. I've never had a roundy CRT implode (knock on wood) and I've got 4 sets and 6 total CRTs, all of which I've handled at some point. The one I cataracted above even got tapped with a hammer on the screen a few times and is fine so I'm not all that worried.
QUOTE]
That someone was wrong!
Any set without either a safety glass or some kind of an integral implosion protection would never pass U/L listing standards.
All the low end roundys at the time used either a 21FJP22 or a 21FBP22 with a tempered safety glass and a rubber sealing ring.
If you notice, the bonded safety glass is not tempered.

So is this a big enough issue that I should transplant the safety glass from my decated Zenith spare or swap that CRT in?

So is this a big enough issue that I should transplant the safety glass from my decated Zenith spare or swap that CRT in?

Keep your Zenith, all Zenith. :D

I'll have to test both tubes to see which is stronger, as IIRC there was a reason that Zenith jug didn't end up in my CTC-4... If it is weaker and or has worse color tracking than the Silver-Glo I'll probably just swap the safety glass.

Hey Tom, great job on that set. I have one that is identical, but with a metal cabinet. I have posted a thread or two about this, but being on the same subject, I thought that you might know something that I need to verify and perhaps correct in my set.

Did you feel or touch the horizontal efficiency (linearity) coil while tooling around under that chassis? Mine is wobbly and supposedly these have a habit of getting brittle and cracking. Just wondering what you found. Do you happen to have an extra by chance? Most people in the know say it needs replacing if it has cracked.

My lin. coil does not seem brittle, but it looks a bit melted. The shaft to the chassis looks almost like it broke long ago and was melted together sloppily with a lighter. It is hard to describe, but I could post a picture if you want. I wonder if the slug is stuck...

I have a spare form that is currently wound with the wire to be used as the horizontal hold coil that I would offer you if there weren't potentially two sets in my collection that might need to have their wire wound on that form.

My lin. coil does not seem brittle, but it looks a bit melted. The shaft to the chassis looks almost like it broke long ago and was melted together sloppily with a lighter. It is hard to describe, but I could post a picture if you want.My lin. coil does not seem brittle, but it looks a bit melted. The shaft to the chassis looks almost like it broke long ago and was melted together sloppily with a lighter. It is hard to describe, but I could post a picture if you want. I wonder if the slug is stuck...

You can post a picture if it's not too much trouble. I found a source for a replacement, so I guess I may as well just replace it since the horizontal and HV sections are so critical in color sets. Most of my collection has always been 40s-50s black and white, so I am a bit lost at times with the many issues that come into play with color sets. I must say that mine came in the door with one beautiful color picture after decades of dormancy. Like yours, I had to replace a few tubes in the HV section and the plate of my H.O. tube was glowing red. Once I replaced the bad tubes it came alive like the day it came off of the assembly line. Of course after about an hour some quirks developed and the color went out. Someone here sent me a crystal that supposedly is a likely culprit with the color problem, but who knows really. Nice of them to help me though. That was over a year ago and I haven't had time to do anything else, but I'm getting the itch bad. I need a nice control door if you see one or have one. Mine is there but has a few dents albeit small.

Tubejunkie: Glad you found a new lin coil. I'll post a picture when I pull the chassis later today. The door on my set is dented too, on the handle. I may try to fix the dents, if I don't like the result I do have a spare door. If whatever door I have left at the end is presentable I'll let you know about it.

Keep your Zenith, all Zenith. :D
That is how it will be. The Zenith tube tests 85% on the red and 76% on all else and the Silver-Glo tests 72% across the board.
The Zenith tube is on the border line of failing the color tracking test though. So if I can't get the colors to track I may have to do a mild rejuv to balance emissions better.

I'm starting to think the ETF CRT tester is tuned to be a bit optimistic in it's readings. It tested the Silver-Glo as ".1 Excellent" which as the set was advertised for the meet is the point where the meter pegs on their tester...On my tester it tests at 72% of full scale which is the lower end of 'good'. I've tested CRTs which make that value look anemic on my tester.

Regarding the slogan about keeping your set all Zenith.
I was just quoting an old advertisement about keeping your GM car all GM, by using only their replacement parts. :yes:

As promised here are the pictures of the lin coil on my set.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2324_zpsbd4edc6c.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2324_zpsbd4edc6c.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2326_zps66816a45.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2326_zps66816a45.jpg.html)


I subbed in my spare Zenith 21FJP22A today.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2318_zpsdef3984b.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2318_zpsdef3984b.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2316_zpsa19b6769.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2316_zpsa19b6769.jpg.html)

About 2 years ago this tube was the first tube of any type which I successfully removed the cataract on. I decided to do the swap the lazy way...Pull the chassis, neck hardware, and degauss frame(I put the set face down for this part) then loosen the adjustable tension band and lift the old CRT out. I then dropped the new CRT in, loosened the screws which connect the CRT mount hardware to the mask, tightened the band snug, tightened the screws back up then tightened the band a pinch more.

http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2320_zpsce11ad7c.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2320_zpsce11ad7c.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2323_zps0fa911c1.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2323_zps0fa911c1.jpg.html)

All that is left is to set up the neck hardware for the new tube before I can work on the electronics again.

Regarding the slogan about keeping your set all Zenith.
I was just quoting an old advertisement about keeping your GM car all GM, by using only their replacement parts. :yes:

I'm 21 years old and suspect that slogan was before my time as I've never heard it. Though it has been a long time since my folks bought GM...The last Non-Honda made car in my family was an 89' Chevy Baretta which was an epic POS from the moment it was built.

Too late to go back on the decision to change the CRT now....Though I guess if there arose some compelling reason to do so I technically could, but I am too LAZY to just do it for no reason. :D I was considering putting the Zenith CRT in for originality and to improve purity days ago anyway....Plus it is safer now in the event of random implosion.

...Though I guess if there arose some compelling reason to do so...

Guess what!....

I powered up the set, waited patiently for a raster and, after far too long, went behind the set to see what the deal was.
I was greeted with this....
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2333_zps0f271cc9.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2333_zps0f271cc9.jpg.html)

http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2332_zps48390844.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2332_zps48390844.jpg.html)

http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2334_zps4e2cb448.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2334_zps4e2cb448.jpg.html)

http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2329_zpsaa745e44.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2329_zpsaa745e44.jpg.html)

:wtf::jawdrop::dammit::dammit::dammit::gigglemad
It would seem the Zenith tube is gassy...So much so that it was loading down the HV to less than 1/5 of what it should be...I tried to get better photos of it, but some LOUD ominous popping noises had me scrambling for the power switch....

I'm very pissed that I went to the effort of installing a POS in my set and that it was not obvious when I tested the tube earlier. It is almost as bad as when I tested the 21AXP in my CTC-4 and found it in the same state. I guess this means I no longer have a spare roundy CRT(or should I say I never had one from the start?).:sadwave:

I guess I should count my blessings that I never bought a roundy with a dead tube thinking I could drop this in. It also tells me what will happen if I get stupid enough to put the 21AXP back in to my CTC-4....

I already ripped the turkey back out and cut the safety glass I siliconed to it(years ago) off...Should I go to the effort to caulk the safety glass from the dud Zenith CRT onto the Silver-Glo?

UGH, what a lousy day!

Well that really sucks! I recently went to go look at an Admiral roundie combo. I tested the tube and it was weak. I did a light cleaning of the guns and it came up well into the good range. So I decided to fire up the set. It came on with HV and had a raster but was arcing inside the neck and had the purple glow. Sometimes CRT testers don't show everything.

Ouch!
I hope you didn't get that CRT from anyone I know. The tube looks vaguely familier. I either traded it or gave it away. They wanted it as a dud.
I couldn't get a decent picture on it to save my soul. The one I had didn't have a cataract on it, for being that old. :sigh:

When I tested the gassy 21AXP in my CTC-4 there was a LOT of neck light. There was some on this tube but you would have to REALLY be looking for it...Which I did when I retested it after running it in the set.

I got the tube for free from Miniman a couple of years back, so I can't complain about it being gassy. It did have a cataract when I got it, and was the first successful cataract removal I ever did. Between the use as a learning tool for cataract removal and the decent safety glass I harvested from it I'd say I got more than my moneys worth out of it. LOL.

I cleaned the good CRT and the harvested safety glass from the bad one, put some foam tape spacers on the tube face and caulked the safety glass on to the good tube. Both the tube and glass have some small scratches so neither will ever be perfect, but it should serve as a decent CRT for the set. In 23 hours when the caulk is dry I'll put the Silver-Glo CRT back in the set this time without a cataract AND WITH a safety glass.

Huh, that's odd. I remember that tube, it's the one with messy looking frit holding it together right? I remember when I got that it tested a little low, but I figured it would work OK if I ever got a set that needed a tube so I kept it in the closet. I don't remember when you got it, but it looks like it got a little gassy over the years. I wonder if it has a glass pinch off or copper?

Huh, that's odd. I remember that tube, it's the one with messy looking frit holding it together right? I remember when I got that it tested a little low, but I figured it would work OK if I ever got a set that needed a tube so I kept it in the closet. I don't remember when you got it, but it looks like it got a little gassy over the years. I wonder if it has a glass pinch off or copper?

That was the one I gave you! I don't remember if it was a freebee or a trade.
I dropped it off at Mark's home in Kenosha, to be given to you.
It came from my 24NC31. It was meant to be a dud. It was just an innocent mixup on your part. After a while, they all look alike.
The only reason I recognized it, is the 6-26 code date. The last Zenith roundy set made.
BTW, I don't trust CRT testers, no matter how good they are! :scratch2:

As promised here are the pictures of the lin coil on my set.
[URL=http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2324_zpsbd4edc6c.jpg.html][IMG]http:/

Thanks for the pics Tom. From the looks of that coil, it has been broken at some point in the past and someone melted it back together. I would think that as long as the spooling area is not broken or collapsed, the conductor wind is continuous, and the shaft is free then everything should be OK with one of these. Mine felt springy at the wound area which would be a problem. I need to double check that to be certain. I have never pulled the chassis as I am trying to wait until I get all the caps that I need. Again, thanks and good luck with your set.

Huh, that's odd. I remember that tube, it's the one with messy looking frit holding it together right? I remember when I got that it tested a little low, but I figured it would work OK if I ever got a set that needed a tube so I kept it in the closet. I don't remember when you got it, but it looks like it got a little gassy over the years. I wonder if it has a glass pinch off or copper?
Yeah it is the one with the messy frit.

Tubejunkie: Your welcome, good luck on yours as well.
Be glad you have a metal cabinet set...The chassis shelf on this set is made of the CRAPPIEST particle board I've seen in any wood cabinet Zenith(or any other make for that matter), and I have Zeniths older and newer than this.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2342_zpsbb6a0ac6.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2342_zpsbb6a0ac6.jpg.html)

I THOROUGHLY degaussed the CRT as well as it's mounting hardware last night, and reinstalled the CRT. After setting the CRT back up I'm getting GREAT purity, and the adjustment range of most of the neck hardware has greatly improved!
I'm going to put this set on hold until the schematic from Dave gets here, then I'll dig in to the vertical.

Here are some pictures of it as of this morning.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2336_zpsf1e968fc.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2336_zpsf1e968fc.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2339_zps9ab970bd.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2339_zps9ab970bd.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2338_zps582a959a.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2338_zps582a959a.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/DSCN2340_zpsf69fa697.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/DSCN2340_zpsf69fa697.jpg.html)

looking MUCH better!

I know wht you mean about the particleboard bottom on these sets. It starts to split at the back of the set. What I did to fix mine was take some carpenter's glue and repair the part that was splitting and also I painted the glue evenly across the underside of the cabinet because some of the particleboard would flake off of the surface. The glue dries clear and holds everything together. They should have used plywood for the bottom. The rest of the cabinet is well made. I prefer Zenith chassis but I always thought RCA had nicer cabinets. I wish I could build a custom cabinet for my Zenith roundie out of all hardwood.

Thanks for the glue tip. I'm using wood glue to fix the split wood lip that is supposed to help hold the back on....And I'm considering repainting the inside of the shelf to hold the surface together.

Thanks for the glue tip. I'm using wood glue to fix the split wood lip that is supposed to help hold the back on....And I'm considering repainting the inside of the shelf to hold the surface together.

When I had my cabinet professionally refinished, I asked about replacing the bottom but I was told it did not look that bad and the cabinet would have to be knocked apart to replace it. I wish it had been replaced. I know someone had a thread where they did replace a Zenith cabinet bottom with 3/4" plywood, cut the holes out for the service saver access panel and cut a groove for the back cover. It turned out really well.

I believe that the bottom panel was not what they were referring to by service saver. I believe that it was a reference to those quick release fasteners that hold the back on, they saved a lot of time versus the dozen or so screws other sets used to hold the back on, which translated to money on charge by the hour house calls.

I believe that the bottom panel was not what they were referring to by service saver. I believe that it was a reference to those quick release fasteners that hold the back on, they saved a lot of time versus the dozen or so screws other sets used to hold the back on, which translated to money on charge by the hour house calls.

Are you sure about that? The removable panel on the bottom precludes pulling the chassis for most under chassis repair. The quick release back cover clips are a nice convenience, though.

I believe that the bottom panel was not what they were referring to by service saver. I believe that it was a reference to those quick release fasteners that hold the back on, they saved a lot of time versus the dozen or so screws other sets used to hold the back on, which translated to money on charge by the hour house calls.

I always thought that the "service saver" idea was based on a combination of the thins mentioned in this thread along with the fact that in the (later I believe) 50s Zenith chassis had the wiring connecting points mounted on those brown strips providing test points above chassis, which I'm sure many will agree would save a ton of time and trouble.

The Zenith roundie is looking much better now! Looks like you might be on the "home stretch" Good work.